Method of producing alloys



Patented Nov. 24, 1 925 UNITED sTA as PATENT OFFICE.

; ALADAB racz, or cmvnmmi amen-rs, 01:10.

METHOD OF. PRODUCING ALLOYS.

V w for its general object the provision of a new and improved method ofproducing alloys especially those wherein the ingredients differconsiderably in melting points. From one aspect this inventionconstitutes an im- 1 provement upon the invention set forth in mycopending application filed February 13, l920, Serial No. 358,555,although not restricted to the ingredients therein defined. In thatapplication I have set forth and claimed a method for producing afinegrained, strong alloy of aluminum and silicon containing a largerproportion of silicon than was ever before associated with aluminum insolid solution form. Considering however that the melting point ofsilicon is about 1400' C. and that of aluminum only about 650 C.,-thealloying of. these sub: stances together offers certain practicaldifii-. culties which I have avoided by the invention herein described.Furthermore, metallic silicon, although obtainable at the present timeat a considerably cheaper rate per pound than aluminum, can be. obtainedby means of the process herein described at; at a very low rate, addedto which is the fact that my improved process resultsin certainby-products whose value is greatly in excess -.of the ingredients. Thisprocess also serves for the ready production of numerous alloys neverbefore available and for the ready reduction of many metals ordinarilyvery difiicult to obtain in metallic form.

The objects of my invention are the provision of a new and improvedprocess for producing metallic silicon in an alloyed state; withaluminum; the provision of a new method of alloying aluminum with aconsiderable quantity of silicon at a comparatively low temperature; theprovision of a method for utilizing a new and hitherto unused source o'fsilicon; the provision of a new and improved method of producingartificial cryolite; the provision of a new and improved method forproducing the alloys of action and itself Application filed larch 18,1920 serial No. ceases.

numerous other metals in conjunction both with aluminum and with othermetals; the provision of a new and improved method for producingnumerous refractory metals in a pure metallic state; while furtherobjects and advantages of the invention will become apparent as thedescription proceeds,

For convenience of description "I will die vide the same into fourheads, although it will be understood that all of the same areexpressions of a single generic idea, said heads being as follows: (1)that wherein the object in view is the'production of an alloy ofaluminum and silicon, the latter being produced entirely by reduction atthe time; (2) that wherein the object is still the production of analloy of aluminum and silicon and alpartof the latter is supplied inpreviously reduced form; (3) thatwherein the method here employed isutilized for the reduction of other metals and their employment eitheralone or alloyed with aluminum;

(4) that whereinthe base of the alloy is I other than aluminum.

Generically speaking, my invention resides in the reduction by aluminumof a double fluoride of some other metal with an alkali metal-such assodium, the reaction being er:

formed in the body of a mass of mo ten metal with which the newlyreduced metal immediately alloys; oxidation being prevented both by thesurrounding body of metal and by the agency of a very fusible flux whichis produced as a part'of the reposssses a high value as a by-product. Itwill be noted in this con nection that under the conditions surroundingthis reaction, many metals are replaced by aluminum which are notordinarily reduced from their oxides by this element.

Firstwconsidering, that specific phase of my invention wherein an alloyof sihcon with aluminunrris desired: I take a quantity of powderedsodium silico-fiuoride (such as is made in rent quantities as a waste.byproduct in t e productionof the fertilizin material known assuperphosphate) an mix the same with powdered or blown-metallic aluminumin the proportion of ap proximatel 5 to 1 (564 to 1 08 to exact). Ipreferably form this, mixture into briquettes or mix the sametogether bymeans of a suitable binder such as a dilute solution' of sodiumsilicate, forming the same into bricks,blocks, chunks or pellets of anysuitable or convenient size. 'NVhen-these are introduced into a bath ofmolten alummu the following reaction occurs:

- ing point of silicon, this being doubtless due to the fact that thesilicon 1s produced in the atomic or nascent condition. The nonmetallicproducts of the reaction float upon the metal in the form of a light,clear, readily fusible slag which constitutes a most excellentelectrolyte for the tallic aluminum.

The slag and metal are separated in any suitable way, as by" pouring orladeling, after which the metal is treated with a com pound of fluorinein the reacting condition. In the absence of thisafter treatment, thealloy when cooled segregates into a coarsely crystalline mass having acompartively small tensile strength an elongation.

Inasmuch as the total amount of slag produced by this reaction mighteasily be much greater than the amount which could be employed as anelectrolyte in aluminum production, I prefer in most cases to mix withthe ingredients above mentioned a quantity of powdered metallic siliconwhich when introduced into the bath in company with the remainingingredients will become quickly absorbed and without the necessity ofgreatly increasing the temperature of the metal as would otherwise 'bethe case. This reaction, therefore, serves not only to incorporatesilicon in the bath by reduction production of me .in situ but alsoserves to facilitate the introduction into the bath of previouslyreduced silicon, and the latter may be resent in any amount up to abouto the total mixture added without necessitating any Inaterialincrease inthe bath temperature. Above this amount it becomes necessary to heat thebath to a higher tempera-- ture although I do not exclude the same frommy invention. Also when the total amount of added silicon becomesgreater than about 30% of the alloy the temperature increases and theyielddecreases. The foregoing constitutes the second aspect ofmyinvention. In either case the resulting slag mustbe removed before thefluoride treatment.can be given.

Passing now to the third aspect of my invention suppose it be desired toalloy. the aluminum with some substance other than silicon, I startwitha double fluoride of .sodium and the desired metal; in. other words,substitute for the double fluoride of sodium and silicon the doublefluoride of sodium with boron, beryllium, scandium,

columbium"; ytterbium, yttrium, lanthanum,

tltan um, zlrconium, cerium, thorlum, vana dium, niobium,tantalum,-chrom1um, iron,

manganese, cobalt, nickel, copper or uranium, whichever 1s desired to bealloyed with the metal of the bath. Possibly other metals could beemployed but these I have tried successfully and while I know thatcertain others like zinc can be treated in this way I apprehend nopractical value outside of the list given. This double fluoride isreduced to powdered form, mixed with aluminum powder in the necessaryproportion, agglomerated into lumps, preferably with the use of abinder, and mtroduced into a bath of molten aluminum in the mannerheretofore described, whereupon the metal in question becomes reducedand alloyed with the aluminum with the production of the same identicalslag as before. In this way it is possible to ;produce an alloy of anycomplexity desired having aluminum as a base, it being merely necessaryto mix the fluorides in the proper proportions.

This reaction may further be utilized for the production of the metalsthemselves; for example, a" double fluoride of zirconium and sodium ismixed with aluminum and added to a bath of aluminum up to as large aquantity as the bath will accommodate, which depends in large measureupon the fusibility of the resulting alloy. The aluminum is alterwardsdissolved out, for example by hydrochloric acid or sodium hydroxide, orother solvent, such a reagent being chosen as will dissolve the one andleave the other. 7 i

The method herein described can also be employed for the introductioninto the alloy of other metals in addition to silicon, merely by theaddition to the silico fluoride mixture of such other metal or metals inthe finely divided form. For example, a quantity of tungsten ormolybdenum can be mixed with the sodium silico-fluoride and aluminum,with 01' without an additional quantity of metallic silicon, and in thisway be introduced into the bath at a temperature far lower than wouldserve for the incorporation of these substances by ordinary methods.This method is not confined to the introduction of the metal inconnection with the silico-fluoride but maybe employed in connectionwith any double fluoride one of whose components is replaceable by thereducing metal under the conditions set forth. For example. it is verydifiicult under ordinary conditions 'to secure an alloy of aluminum andnickel owing to their widely dissimilar melting points; but by adding toa bath of molten'aluminum a mixture of sodium nickel double fluoride,aluminum powder, and powdered nickel, this absorption and solution takesplace at a comparatively low temperature almost quant1tatively, with thegreatest of ease and the pro;

duction of a perfectly fusible and easily Separated sla Passing now tothe fourth aspect of my invention above enumerated, this process is notlimited to the production of alloys hav ing an aluminum base but isequally applicable to the production of alloys of any metal with anyother metal, although I conceive it will have its greatest importance inconnection with alloys whose ingredients differ greatly in meltingpoint. Thus to alloy zirconium with iron, .the sodium zirconium doublefluoride is mixed with aluminum and introduced into a bath of molteniron. If care be taken to briquette or agglutinate the ingredientsproperly the reaction will be almost perfectly quantitative,substantially all the zirconium being reduced and substantially none ofthe aluminum being dissolved in the bath. Likewise to alloy molybdenum,tungsten, uranium or vanadium with cast iron or any such metal as canreadily be secured in metallic form, or in the form of a ferro-metal, Imix a quantity of the double fluoride of iron and sodium with therequisite amount of aluminum powder and the desired amount of the metalto be incorporated. \Vhen this mixture is introduced into the bath ofmolten iron the desired effect is produced. I have suggested the irondouble fluoride in order to prevent contaminating the alloy with anythird metal, although any double fluoride can be used which contains ametal not injurious to the finished product, such as manganese. ployedin the production of any alloy but oii'ers some of its greatestadvantages in connection with the preparation of alloys oi the are earthmetals which are ordinarily extremely dillicult to produce becauseof-thc difliculty of their independent reduction which is here entirelyavoided.

It will be understood that a great. many modifications and combinationsof the steps and procedures above outlined can be made and all such Iclaim and assert as a part of my invention limiting myself in nowiseexcept as specifically recited in the'claims hereto annexed.

Having thus described my invention, what I claim is: a

1. The process of producing alloys which contains the step of treatingwith aluminum a double fluoride of sodium with one of the componentmetals in a molten bath of the other component metal, whereby thealuminum replaces the first named component metal from its compound withthe fluorine.

2. The process of producing alloys which This method can be em moltenbath of onset the component metals a double fluoridewith an alkali metalof the other component metal mixed with suflicient powdered aluminum toreplace such other metal from. the fluoride. x

' The process of reducing metal which resides in the partial reductionby aluminum of adouble fluoride with sodium ofthc metal to be produced,in the body of a mass of molten metal at a ten'iperature at least ashigh as the melting point of aluminum, whereby the metal is reducedwithin the body of such molten metal and becomes im mediately alloyedtherewith.

4:. The process of producing an alloy of two metals of dissimilarmelting points which contains the step .of treating with aluminum adouble fluoride of an alkali metal with the less fusible metal in amolten bath of the more fusible metal. a

5; The, process of producing an alloy of two metals of dissimilarmelting points which contains-the step of introducing into a'. moltenbath of the more fusible metal a double'fluoride with an alkali metal ofthe less fusible metal 'mixed with sufficient powdered aluminum toreplace-such last metalqtrom the fluoride, the temperature of the bathbeing maintained below the melting point of said last metal.v

6. The process of p'roducin alloys which contains the step ofintroducing into a molten bath of one of the component metals anintimate mixture of the othen component metal in powdered form togetherwith powdered aluminum and the double fluoride with sodium of a metalwhich aluminum will replace the aluminum being present in substantiallythe correct quantity to replace such last mentioned metal molecularly.

v7. The process of producing binary alloys which contains the step ofintroducing into a molten bath of one ofthe metals an intimate mixtureof the other component metal in powdered form with powdered aluu'unumand the double 'I'hioride'with, an alkali metal surface of a moltenmetal which is capable.

of alloying with such first metal under circumstances which prevent thesegregation of the mixture, and finally separating the components ofsaid alloy.

, 9. The process of producing a metal which contains the steps ofpreparing a double fluoride of such metal with an alkali, mixing suchdouble fluoride intimatelywith a secand in quantity sn cient to replacethe first metal, and elevating the temperature of the mixture to thereaction point under fconditions which prevent the access of air;

10. The process of producing an alloy of aluminum and silicon whichcontains the step of introducing into a bath of molten aluminum anagglomeratedmixture of sodium silico-fluoride and aluminum powder.

11. The process of producing an alloy of aluminum and silicon whichcontains the step ot'subjectingsodium silico-fluoride to the reductioneffect of an excess of metallic aluminum at a temperature above themelting point of aluminum.

12. The process of producing an alloy of aluminum and silicon whichcontains the step of introducing into a bath of molten aluminum anagglomeratedmixture of so dium silicofluoride, aluminum powder andmetallic silicon. I 13. A composition of matter for use in making alloysof aluminum and silicon consisting essentially of sodium fluo-silicatemixed with the amount ofpowdered aluminum requisite to the reduction ofthe silicon, said mixture agglomerated into-lump form. ll. A compositionof matter for use in making alloys of aluminum and silicon consistingessentially of sodium fluo-silicate' mixed with the amount ofpowderedaluminum requisite to thereduction of the sili= con and w1th anaddedamount of powdered silicon the whole being agglomerated into lumptorm.

15. The process of producing an alloy of a metal whose oxide isrefractory which consists in forming a double" fluoride of the same withsodium, pulverizing such fluoride,- mixing the same with the quantity ofpowdered aluminum necessary to replace the metal first mentioned andadding the Same to a molten bath of the metal with which the first metalis to 'be alloyed.

1.6. In the process of preparing alloys, by adding to a molten bath ofone component metal a mixtureof powdered aluminum together wlth afluoride of the other component metal which aluminum will reduce with inadding to such mixture 2, quantity of' powdered metal and agglomeratiugthe whole mass before adding-it to the molten bath. 4 4

18. The process of producin alloys which contains the steps ot' firstproc ucing a mixture of fluorides, one of which contains one ot' theingredients of the alloy and-another of which -is such a fluorideas willcombine with aluminum fluoride to produce a't'uslble slag, mcorporatmgtherewlth enough pow- 'dcred aluminum to displace such first metal,

mixing therewith a quantity of .powdered metal which 1s-to constituteone of the lngredicnts of the alloy, and adding such mixture to a moltenbath of one of the ingredients of the alloy. 4 a

19. The method of producing alloys which consists in fusing the metal oflowestmclting point and introducing therein the other metal in finelydivided condition mixed with a double fluoride of an alkali metalnndsome other metal and enough powdered aluminum to replace said lastmentioned metal.

20. The method of. reducing the metals whose oxides'are refractory whichconsists in producing thedouble fluoride of such metal combined with analkali metal such assodium. mixing such double fluoride with an amountof powdered aluminum sufficient to reduce thc tirst mentioned metal,agglome1'at1ng the mixture into lumps, and adding the same to a bath ofmolten aluminum. i In testimony whereof, I hereunto alilx my signature.

ALADAR PACV.

